Submission #1126690

#	Time	Username	Problem	Language	Result	Execution time	Memory
1126690		ShadowShark	Cities (BOI16_cities)	C++20	100 / 100	1783 ms	40016 KiB

cities

#include <bits/stdc++.h>
using namespace std;

const int maxN = 1e5 + 5; const long long inf = 1e14;
vector<pair<int, int>> adj[maxN];
long long dis[32][maxN]; int n, k, m, pos[10];

void dijkstra(int mask) {
    priority_queue<pair<long long, int>, vector<pair<long long, int>>, greater<pair<long long, int>>> pq;
    for (int i = 1; i <= n; i++)
        if (dis[mask][i] < inf) pq.push({dis[mask][i], i});

    while (pq.size() > 0) {
        auto [len, u] = pq.top(); pq.pop();

        if (dis[mask][u] != len) continue;

        for (auto [v, w]: adj[u])
            if (dis[mask][v] > len + w) {
                dis[mask][v] = len + w;
                pq.push({dis[mask][v], v});
            }
    }
}

int main() {
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    cin >> n >> k >> m;

    for (int i = 1; i <= k; i++)
        cin >> pos[i];

    for (int i = 1; i <= m; i++) {
        int u, v, w;
        cin >> u >> v >> w;

        adj[u].push_back({v, w});
        adj[v].push_back({u, w});
    }

    for (int mask = 1; mask < (1 << k); mask++)
        for (int i = 1; i <= n; i++)
            dis[mask][i] = inf;
    for (int i = 1; i <= k; i++)
        dis[(1 << (i - 1))][pos[i]] = 0;

    for (int mask = 1; mask < (1 << k); mask++) {
        for (int i = 1; i <= n; i++)
            for (int submask = mask; submask > 0; submask = (submask - 1) & mask)
                dis[mask][i] = min(dis[mask][i], dis[submask][i] + dis[mask ^ submask][i]);

        dijkstra(mask);
    }

    cout << *min_element(dis[(1 << k) - 1] + 1, dis[(1 << k) - 1] + n + 1);
    return 0;
}

• Subtask 1: 22 / 22
• Subtask 2: 14 / 14
• Subtask 3: 15 / 15
• Subtask 4: 23 / 23
• Subtask 5: 26 / 26